Hackaday Prize Entry: Density Altitude Gauge

Despite what extraordinarily overpowered quadcopters suggest, the air pressure of whatever a flying machine flys at is extremely important. Pressure is dependent on altitude and temperature, and there are hundreds of NTSB investigations that have concluded density altitude – pressure altitude corrected for nonstandard temperature variations – was the reason for a crash. Normally density altitude is computed through a slide rule or a flight computer, with the pilot entering in altitude and temperature, but somehow accidents still happen. For his entry to The Hackaday Prize, [Neil McNeight] is building an automated density altitude calculator to automate the process entirely.

Instead of having a pilot enter the altitude and temperature into a flight computer manually, [Neil]’s device grabs the current altitude from a GPS unit, and reads the temperature with a tiny sensor acquired from SparkFun. With just a little bit of math, this device will spit out the altitude an airplane or ‘copter thinks it’s at.

While the FAA won’t allow instruments that are cobbled together on a breadboard, this does have a few applications in the RC world. There are extremely high performance racing quadcopters out there now, and knowing how the craft will perform before flying it will save a few props.

The 2015 Hackaday Prize is sponsored by:

Hackaday Links: May 17, 2015

Here’s a worthwhile Kickstarter for once: the Prishtina Hackerspace. Yes, that’s a Kickstarter for a hackerspace in Kosovo. Unlike most hackerspace Kickstarters, they’re already mostly funded, with 20 days to go. If we ever get around to doing the Istanbul to Kaliningrad hackerspace tour, we’ll drop by.

Codebender is a web-based tool that allows you to code and program an Arduino. The Chromebook is a web-based laptop that is popular with a few schools. Now you can uses Codebender on a Chromebook. You might need to update your Chromebook to v42, and there’s a slight bug in the USB programmers, but that should be fixed in a month or so.

Here’s a great way to waste five minutes. It’s called agar.io. It’s a multiplayer online game where you’re a cell, you eat dots that are smaller than you, and bigger cells (other players) can eat you. [Morris] found the missing feature: being able to find the IP of a server so you can play with your friends. This feature is now implemented in a browser script. Here’s the repo.

The FAA currently deciding the fate of unmanned aerial vehicles and systems, and we’re going to live with any screwup they make for the next 50 years. It would be nice if all UAV operators, drone pilots, and everyone involved with flying robots could get together and hash out what the ideal rules would be. That’s happening in late July thanks to the Silicon Valley Chapter of AUVSI (Association for Unmanned Vehicle Systems International).

SOLAR ROADWAYS!! Al Jazeera is reporting a project in the Netherlands that puts solar cells in a road. It’s just a bike path, it’s only 70 meters long, and it can support at least 12 tonnes (in the form of a ‘fire brigade truck’). There’s no plans for the truly dumb solar roadways stuff – heating the roads, or having lanes with LEDs. We’re desperately seeking more information on this one.

Hackaday Prize Entry: Multispectral Imaging For A UAV

At least part of the modern agricultural revolution that is now keeping a few billion people from starving to death can be attributed to remote sensing of fields and crops. Images from Landsat and other earth imaging satellites have been used by farmers and anyone interested in agriculture policy for forty years now, and these strange, false-color pictures are an invaluable resource for keeping the world’s population fed.

The temporal resolution of these satellites is poor, however; it may be a few weeks before an area can be imaged a second time. For some uses, that might be enough.

For his Hackaday Prize entry (and his university thesis), [David] is working on attaching the same kinds of multispectral imaging payloads found on Earth sensing satellites to a UAV. Putting a remote control plane up in the air is vastly cheaper than launching a satellite, and being able to download pictures from a thumb drive is much quicker than a downlink to an Earth station.

Right now, [David] is working with a Raspberry Pi and a camera module, but this is just experimental hardware. The real challenge is in the code, and for that, he’s simulating multispectral imaging using Minecraft. Yes, it’s just a simulation, but an extremely clever use of a video game to simulate flying over a terrain. You can see a video of that separated into red, green, and blue channels below.

The 2015 Hackaday Prize is sponsored by:

Continue reading “Hackaday Prize Entry: Multispectral Imaging For A UAV”

UAV Coaxial Copter Uses Unique Drive Mechanism

Personal UAV’s are becoming ubiquitous these days, but there is still much room for improvement. Researchers at [Modlab] understand this, and they’ve come up with a very unique method of controlling pitch, yaw, and roll for a coaxial ‘copter using only the two drive motors.

In order to control all of these variables with only two motors, you generally need a mechanism that adjusts the pitch of the propeller blades. Usually this is done by mounting a couple of tiny servos to the ‘copter. The servos are hooked up to the propellers with mechanical linkages so the pitch of the propellers can be adjusted on the fly. This works fine but it’s costly, complicated, and adds weight to the vehicle.

[Modlab’s] system does away with the linkages and extra servos. They are able to control the pitch of their propellers using just the two drive motors. The propellers are connected to the motors using a custom 3D printed rotor hub. This hub is specifically designed to couple blade lead-and-lag oscillations to a change in blade pitch. Rather than drive the motors with a constant amount of torque, [Modlab] adds a sinusoidal component in phase with the current speed of the motor. This allows the system to adjust the pitch of the blades multiple times per rotation, even at these high speeds.

Be sure to watch the demonstration video below. Continue reading “UAV Coaxial Copter Uses Unique Drive Mechanism”

Quadcopter Beer Delivery System

One of the major design challenges when it comes to building an efficient quadcopter is weight. The idea here is that the more you can trim down the weight of the frame, motors, and circuitry, the longer the batteries will last. Or, in [dalbyman]’s case, the more beer it can carry.

[Dalbyman]’s housemate built the actual quadcopter, but then [dalbyman] got a little inebriated and decided that, while the quadcopter was exciting on its own, it would be even better with this modification. The actual device is a modified Pringles can with two servo motors on the bottom with arms that hold the beer. A parachute is attached to the beverage can and the assembly is loaded in. With a simple press of a button, the servos turn the arms and the beer falls out of the tube. Hopefully the parachute deploys and gently (and accurately) floats the beer to the thirsty person on the ground!

This project is a simple step that goes a long way towards a beer delivery system even Amazon could be proud of, and also shows off the capabilities of quadcopters in general. Perhaps the next step could be to automate the beer delivery system!


Reverse Engineering the Proto X Quadcopter Radio

Just a few years ago, palm sized radio controlled toys were nothing more than a dream. Today, you can find them at every mall, toy store, and hobby shop. [Alvaro] couldn’t resist the tiny Estes Proto X quadcopter. While he enjoyed flying the Proto X, he found that the tiny controller left quite a bit to be desired. Not a problem for [Alvaro], as he embarked on a project to reverse engineer the little quad.

Inside the quadcopter and its lilliputian radio, [Alvaro] found a STM8 based processor and an Amiccom A7105 2.4G FSK/GFSK Transceiver radio. The A7105 is well documented, with datasheets easily obtained on the internet.  The interface between the processor and the radio chip was the perfect place to start a reverse engineering effort.

With the help of his Saleae logic analyzer, [Alvaro] was able to capture SPI data from both the quadcopter and the transmitter as the two negotiated a connection. The resulting hex files weren’t very useful, so [Alvaro] wrote a couple of Python scripts to decode the data. By operating each control during his captures, [Alvaro] was able to reverse engineer the Proto X’s control protocol. He tested this by removing the microcontroller from the remote control unit and wiring the A7105 to a STM32F4 dev board. Connecting the STM32 to his computer via USB, [Alvaro] was able to command the quad to take off. It wasn’t a very graceful flight, but it did prove that his grafted control system worked. With basic controls covered, [Alvaro] knocked up a quick user interface on his computer. He’s now able to fly the quadcopter around using keyboard and mouse. Not only did this prove the control system worked, it also showed how hard it is to fly a real aircraft (even a tiny model) with FPS controls.

The Estes Proto X is actually manufactured by Hubsan, a China based manufacturer best known for the x4 series of mini quadcopters. Since the Proto X and the x4 share the same communication protocol, [Alvaro’s] work can be applied to both. With fully computer controlled quads available for under $30 USD, we’re only a few cameras (and a heck of a lot of coding) away from cooperative drone swarms akin to those found in the University of Pennsylvania GRASP Lab.

Continue reading “Reverse Engineering the Proto X Quadcopter Radio”

An Extremely Tiny 5.8GHz FPV Transmitter

Flying RC aircraft with a first person view is the latest and greatest thing in the hobby. In a fact that I’m sure will be shocking to 90% of people, you don’t need to buy a Phantom quad fly FPV. The guys at Flite Test show how you can build a tiny 5.8GHz FPV transmitter for under $100.

The parts used for this build are pretty much jelly bean parts at this point, but [Peter] at Flite Test is going for extremely lightweight parts for this build. He found an NTSC board camera that only weighs 1g and added a wide-angle lens. The transmitter is a tiny 200mW module that only weighs about 2g.

Why are the Flite Test crew going for small and light FPV setups? They just launched a new line of planes that can be built from a single piece of foam board. If you have a small micro quad, you can easily add FPV to it with this rig.